Ventilation with perfluorocarbon (PFC) liquids preserves the lungs and maintains gas exchange during end-stage adult and infant respiratory failure. The applicants propose to develop a new type of liquid ventilator with greatly enhanced gas exchange capability. The ventilator uses a recently patented mode of liquid delivery which circumvents the gas exchange limitation imposed by the slower diffusion of gases in PFC liquid, compared to air. A continuous intratracheal circulation of PFC liquid through a double lumen catheter with superimposed delivery of liquid tidal volume removes airway dead space ventilation and facilitates respiratory gas diffusion through airway eddy currents. Preliminary data in piglets indicate an increase in CO2 clearance using this mode of liquid delivery. During phase I, Mallard Medical Company which has extensive experience in ventilator development and production, will develop and deliver a prototype ventilator with high output capability and precise wave form control. The investigators propose to optimize ventilatory parameters to maximize CO2 clearance and compare maximal CO2 clearances and blood gas values between the new mode of ventilation and conventional tidal liquid ventilation in newborn piglets. They will also ventilate piglets for 6 hours at optimal settings and examine the lungs for histologic evidence of tissue injury. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE